Production of fluids from subterranean earth formations may be increased by drilling multiple wellbores out of and away from a main wellbore to exploit productions zones which cannot otherwise be effectively connected to the main wellbore. Various techniques have been developed for developing multiple wellbores away from a main wellbore, sometimes known as "side-tracked" or multilaterals, wherein a drill guide or whipstock is placed in the main wellbore at a selected interval and a drill motor, disposed on the end of coilable tubing or on the end of a threaded drill string which may be steerable, is then used to drill a branch wellbore in a direction away from the main wellbore. Several branch wellbores may be drilled away from the main wellbore and completed in a substantially conventional manner by installation of casing or, if the formation conditions permit, the branch wellbores may be left in an "open hole" condition. Since these wellbores are spaced along the main wellbore, fluid communication through the main wellbore to the surface must be provided, which often necessitates the removal of the drill guide equipment or whipstock, once the branch wells are completed. Accordingly, reentry into the branch wellbores from the surface with tools and equipment is difficult and expensive to carry out.
A complication of producing fluids from multiple wellbores which branch out from a main wellbore is that of fluid flow control. One or more of the branch wellbores may cease producing desirable fluids and require to be shut in. In any case, from time to time, testing operations are desired to be carried out to determine the production characteristics of each of the branch wellbores. In this regard, of course, it is conventional to provide a flow control valve at a position in a well which will permit easy access to the valve for operation. In a single wellbore this flow control valve may be placed at or near the surface. However, in multiple wells which extend from a common wellbore, control valves for each well must be placed in each respective branch wellbore. Accordingly, access to these valves to operate same is difficult, if not impossible, to achieve while production continues from one or more of the other wellbores, since placement of tools or retrieval devices normally conveyed into the well on flexible cables, coilable tubing or other mechanical means cannot be easily carried out. Remote control of flow control valves in multiple wells is therefore highly desired and it is to this ,end that the present invention has been developed.